I used to use it for things like equations, but now rarely do even for that. I'd only ever use it for scientific document creation / editing and these days I just use Word of all things. No, seriously. It's evil - but I consider it the lesser of 3 evils (LaTeX and OO being the other 2.)

It was more useful before decent WYSIWYG editors came about, now it just feels like writing in code when it's not required.

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Save the whales, feed the hungry, free the mallocs.

I was not aware that LaTeX could be used for website content - I typically only use it when creating pdf documents and reports. The editor I use for that is TexMakerX, which offers some nice features like autocompleting commands and highlighting any errors in the code. It can sometimes highlight "errors" that aren't really there, but it will usually compile fine regardless. But this is for making pdfs - I've never used it exclusively for website content.

TeXworks, Programmer's Notepad, WinShell, Emacs and Notepad++ also support LaTeX, so those would also be some other alternative editors.